Rehabilitation of the maxilla with computer-assisted lapless surgery according to virtual preoperative planning: A case report

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1 original article Rehabilitation of the maxilla with computer-assisted lapless surgery according to virtual preoperative planning: A case report Abstract / Introduction: Computer-guided surgery combined with CAD/CAM technology is a useful technique for placement of osseointergated dental implants with utmost accuracy, since it employs virtual planning technology which allows visualization by a computer software of the relationship between one s prosthetic needs and the amount of bone available. Objective: he aim of this study was to report a case of maxillary rehabilitation with the use of the Neoguide system (Neodent, Curitiba, Brazil), with the aid of computer-guided lapless technique and immediate loading. Methods: After pre tomographic preparation and virtual planning, eight Titamax EX Morse taper implants (Neodent, Curitiba, Brazil) were placed using a prototyped surgical guide. After implant placement, panoramic radiographs and CT scans were performed. Subsequently, a ixed implantsupported denture was installed. Conclusion: he use of computer-guided lapless surgery with immediate loading proved a valuable resource in maxillary rehabilitation, with reduced surgical time and decreased postoperative symptoms such as pain, swelling and inlammation. Keywords / Dental implants. Computer-guided surgery. Fixed implant-supported prosthesis. Jean UHLENDORF Professor, Latin American Institute of Dental Research and Education. Yuri UHLENDORF Professor, Latin American Institute of Dental Research and Education. Jaques LUIZ Professor, Latin American Institute of Dental Research and Education. José Antônio BRESSANI Professor, Anhanguera University (UNIDERP) and Union of Dentists Campo Grande and Cuiabá Brazil. Willian de ARAÚJO Specialist in Product Management and Engineering, Positivo University. How to cite this article: Uhlendorf J, Uhlendorf Y, Luiz J, Bressani JA, Araújo W. Rehabilitation of the maxilla with computer-assisted flapless surgery according to virtual preoperative planning: A case report. Dental Press Implantol July-Sept;8(3): doi: Submitted: November 10, Revised and accepted: July 04, 2014 Contact address: Jean Uhlendorf Rua Jacarezinho, 656 CEP: Curitiba/PR Brazil juhlendorf@yahoo.com.br» The authors Jean Uhlendorf and Willian de Araújo report having employment relationship with the company Neodent which is mentioned throughout this article.» Patients displayed in this article previously approved the use of their facial and intraoral photographs. 66 Dental Pres Implantol July-Sept;8(3):66-75

2 Rehabilitation of the maxilla with computer-assisted flapless surgery according to virtual preoperative planning: A case report INTRODUCTION he concept of computer-guided surgery emerged as a result of the development of prototyping processes. he technique consists in transferring to a virtual model the images of a patient s bone structure combined with an orientation guide, thus enabling the reproduction of a virtual plan by means of a prototyped surgical guide manufactured on the basis of CAD/CAM technology. 1 he prototyped surgical guide allows lapless implant placement and the application of an immediate loading protocol. he clinical applicability and reliability of this resource has been proven by several studies. 2-6 Computer-guided surgery helps professionals to place dental implants with utmost accuracy, since it employs virtual planning technology which allows visualization by a computer software of the relationship between one s prosthetic needs and the amount of bone available. he implant site is critical to achieve a successful rehabilitation, whereas computer-guided technique results not only in superior accuracy when placing implants with bone anchorage, but also in improved occlusal emergence, thereby allowing implants to be inserted in a predictable, reliable manner his article reports a clinical case in which computer-guided lapless technique with immediate loading was employed to rehabilitate an edentulous maxilla. CLINICAL CASE REPORT A 49-year-old, male patient presented at the clinic of the Latin American Institute of Dental Research and Education (ILAPEO) for evaluation. Clinical examination revealed he presented with various upper teeth missing, a number of teeth indicated for extraction, and wore a partial removable denture. he latter was his chief complaint. Panoramic radiograph (Fig 1) and laboratory tests were requested. Figure 1. Initial panoramic radiograph. Dental Pres Implantol July-Sept;8(3):

3 Uhlendorf J, Uhlendorf Y, Luiz J, Bressani JA, Araújo W he irst phase of treatment consisted in extracting the remaining upper teeth and fabricating a temporary complete denture. After healing, the preparation necessary before CT scanning was performed. It consisted of a diagnostic wax up of the maxilla made to establish the vertical dimension and determine esthetic and functional parameters. he wax up was duplicated with colorless acrylic resin so as to obtain a CT guide (Fig 2). In this guide, ive well distributed and asymmetric gutta-percha markings were made. he tomographic guide was tested and adjusted, an interocclusal relief was fabricated and the patient was referred to CT scanning. Image acquisition was based on the double scanning technique: A CT scan was performed with the guide and the interocclusal record in place, and then a new CT scan with just the tomographic guide was taken. To this end, an i-cat (Imaging Sciences, Hatield, USA) Cone Beam Computed Tomography (CBCT) scanner was used. he images obtained with CBCT in DICOM format were converted with Neoguide Builder software (Neodent, Curitiba, Brazil). Neoguide Planner software (Neodent, Curitiba, Brazil) was used to perform a virtual planning of implants and prosthetic components (Fig 3), so as to allow bone anchorage of implants and the emergence of the prosthetic screws to be distributed in an optimal manner for the case. Based on this planning, a prototyped surgical guide was fabricated (Neodent, Curitiba, Brazil) with a view to transferring the virtual planning to the surgical procedure. Figure 2. Tomographic guide with gutta-percha markings. 68 Dental Pres Implantol July-Sept;8(3):66-75

4 Rehabilitation of the maxilla with computer-assisted flapless surgery according to virtual preoperative planning: A case report Figure 3. Virtual planning using the Neoguide Planner software. he surgical guide was disinfected through immersion in 0.12% chlorhexidine digluconate. Anesthesia was applied with a solution based on 2% mepivacaine hydrochloride with epinephrine 1:100,000 (DFL, Rio de Janeiro, Brazil). Application was performed slowly and gradually so as to avoid swelling in the region, which could have made it diicult to place the surgical guide. he guide was stabilized with the use of a self-drilling graft screw in the center of the palate along with three ixing pins (Fig 4). With the use of the Neoguide surgical kit (Neodent, Curitiba, Brazil), surgical instrumentation followed the progressive sequence of drills. he in and out movements of the drills was performed frequently with constant and copious irrigation. Eight Titamax EX Morse taper implants (Neodent, Curitiba, Brazil) (Fig 5) were installed. Installation was inished with a torque wrench (Fig 6). Installation torque was above 32 N/cm 2 for all implants, which allowed the use of immediate loading. After lapless implant placement (Fig 7), the surgical guide was removed and mini-pillartype intermediaries (Neodent, Curitiba, PR, Brazil) were installed. Immediately thereafter, postoperative panoramic radiographs (Fig 8) were taken. A transfer impression was performed with the aid of the CT guide, and a deinitive hybrid ixed prosthesis was fabricated and installed (Fig 9) by following the protocol of immediate loading with the technique of passive cementation, 12 thus immediately restoring patient s aesthetics and function (Fig 10). Dental Pres Implantol July-Sept;8(3):

5 Uhlendorf J, Uhlendorf Y, Luiz J, Bressani JA, Araújo W Figure 4. Fixing the prototyped surgical guide. Figure 5. Flapless implant placement with the surgical guide. 70 Dental Pres Implantol July-Sept;8(3):66-75

6 Rehabilitation of the maxilla with computer-assisted flapless surgery according to virtual preoperative planning: A case report Figure 6. Finishing implant installation with a torque wrench. Figure 7. Flapless implant placement. Dental Pres Implantol July-Sept;8(3):

7 Uhlendorf J, Uhlendorf Y, Luiz J, Bressani JA, Araújo W Figure 8. Postoperative panoramic radiograph. Figure 9. Prosthesis in place, intraoral view. Figure 10. Prosthesis in place, patient smiling. Postoperative control was carried out by means of clinical and radiographic examination, including a CT scan (Fig 11) and a panoramic radiograph (Fig 12). he prosthesis was removed and each implant was tested individually. All implants were successful and showed no irreversible or persistent signs and symptoms such as pain, infection, neuropathy, paresthesia or mobility. Moreover, there was no evidence of peri-implant radiolucency on the radiographs. DISCUSSION CAD/CAM technology has been increasingly used to address many issues in Implantology. he possibility of conducting virtual 72 Dental Pres Implantol July-Sept;8(3):66-75

8 Rehabilitation of the maxilla with computer-assisted flapless surgery according to virtual preoperative planning: A case report Figure 11. Postoperative CT images. Figure 12. Final panoramic radiograph. planning and fabricating a prototyped surgical guide results in increasingly safe and accurate diagnosis and treatment planning. his technique streamlines the surgical procedure, thereby enabling the use of virtual planning for placing osseointegrated implants. 7-9 With regard to the number of implants required for maxillary implant-supported rehabilitation, studies suggest that four to six implants are enough to attain longterm success. However, when bone is abundant, a greater number of implants can result in a better distribution of forces acting on the rehabilitation, 17 thus avoiding the need for a distal cantilever. he location of implants should also favor occlusal balance, Dental Pres Implantol July-Sept;8(3):

9 Uhlendorf J, Uhlendorf Y, Luiz J, Bressani JA, Araújo W creating a favorable support polygon, thereby minimizing possible biomechanical risks and prosthetic complications For these reasons, the authors chose to install eight implants so as to ensure good distribution in view of patient s prosthetic needs. he insertion torque measured at the time of implant placement was found to be between 32 and 45 N/cm 2. hese are the benchmarks found in the literature, and are seen as a decisive parameter for applying the technique of immediate loading. hese values made immediate loading possible in the case reported herein, thereby bringing to the patient the added beneit of not having to wait for osseointegration to occur. In the present case, the technique of guided surgery ofered important advantages: reduced surgical time; decreased postoperative symptoms, such as pain, swelling and inlammation; and, as a result, faster recovery. When properly indicated and applied, this technique ofers reduced patient morbidity, greater surgical precision, increased patient s comfort and safety for the professional. Moreover, it minimizes surgical errors and potential damage to anatomical structures. 1-6,9-11,13-16 As it is the case with all techniques, there are indications and contraindications to be considered before choosing the computer-guided technique. here must be an adequate amount of bone, good mouth opening, as well as suicient keratinized tissue, as computer-guided surgery limits the possibility of manipulating soft tissues According to studies comparing virtual planning and implants placed by means of computer-guided surgery, there is no guarantee of absolute precision. Based on a literature review, D Haese et al 26 concluded that angular variations may vary from 0.9 to 4.5 degrees. Impaired visibility during instrumentation and installation, and limited tactile control during surgery should also be considered. he various preoperative impression phases, the fabrication of the tomographic guide, CT scanning and ixation of the surgical guide should be carefully performed, given that minor errors might add up during these steps and result in signiicant deviations. 27 hese factors underscore the impossibility of clinically applying the technique in cases of severe atrophy, high complexity and borderline cases, in which bone quantity is insuicient. A margin of safety should be adopted to avoid potential risks, such as: implant failure, fenestration and damage to important anatomical structures It is essential to understand the indications and limitations of the technique, as well as follow the steps of pre-ct preparation in a judicious manner so as to achieve favorable and successful implant placement while reproducing the preoperative virtual planning. CONCLUSION he use of immediate loading associated with the computer-guided lapless technique proved a valuable resource in maxillary rehabilitation. here was a reduction in surgical time and a decrease in postoperative symptoms, such as pain, swelling and inlammation. Moreover, the patient was completely satisied with the success of treatment. 74 Dental Pres Implantol July-Sept;8(3):66-75

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